Low Conductivity of Copper Wire

Abstract

As one of very numerous instances which have come under his notice, Sir William Thomson desires to make known the following case of the employment of inferior copper wire in the construction of electrical apparatus. He received lately from a Glasgow bell-hanger a large quantity of cotton-covered copper wire, which was being largely used for the coils of electric bells, and upon having it tested very accurately by means of his new Multiple Arc Conductivity Box, its resistance per metre-gramme was found to be no less than 0.439 of a B.A. unit; that of ordinarily good copper wire for such purposes being about 0.16 of a B.A. unit.